There is a need for novel treatments for pain and inflammation, particularly in the treatment of oral and dental pain. Some current agents may be ineffective and can, for example, come with unacceptable side effects. Furthermore, there is a growing concern about the overuse of opioid pain treatments.
Hydrogels can be used as a vehicle for the delivery of drugs and other therapeutically active agents. They refer to a network of hydrophilic polymer chains that are generally found as a colloidal gel in which water is the dispersion medium. Hydrogels are highly absorbent (they can contain over 99.9% water) natural or synthetic polymers and can also possess a degree of flexibility very similar to natural tissue, due to their significant water content (“Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)”. Pure and Applied Chemistry 83 (12): 2229-2259. 2011).
Hydrogels are characterized by the inclusion of water which acts to disperse the polymer into a colloidal mass. Unfortunately, the presence of water limits the utility of these products to water sensitive materials or environments where moisture is contraindicated. The physical properties of water also dictate the physical properties of the hydrogel, such as reactivity to acids and bases. Thus, there are applications, including the delivery of drugs and other therapeutically active agents, where anhydrous hydrogels (i.e., hydrogels without the aqueous limitations) may be preferred.